Should we really think those who excercise letters of marque wait for further “authorization” from the people who are served such letters? The letter is just a formal way of saying one has been sent under the authority of his country to take and break another’s stuff.
We are authorized to send private individuals to do this, and those individuals may do so without fear of being prosecuted by our country. The other country will obviously not recognize it as legal. Who cares? It’s end of story. Their stuff is gone, and there isn’t a thing they can do about it unless they want to come, fight, and lose even more stuff.
Of course we are not obligated to respect letters of marque served upon our own interests. That would be ridiculous. Our military and law enforcement are permitted, if not obligated, to engage anyone who tries.
Perhaps you misunderstand how letters of marque and reprisal work.
One does not "serve" the letters to another party.
One carries them.
This is the scenario for which these letters were originally designed: England and Spain, say, are at war or not on good terms. England issues letters of marque and reprisal to privateers, authorizing them to attack Spanish ships and capture Spanish citizens. An authorized privateer spots a Spanish ship off the coast of France. They seize the ship. The French authorities demand to know what is going on and what entitles these Englishmen to attack France's allies in French waters.
The privateer produces the letters he is carrying, showing that he is authorized to do so by the government of England and that, although a private individual, he is acting by English authority.
The French then have to decide whether to imprison a representative of the English government.
If he was purely a private citizen, the privateer would have been thrown in chains by the French and charged with piracy. But because he holds letters, it is now a international incident which has diplomatic repercussions. The French have to let him go with his booty, or the French ambassador is going to have to explain to the English government why one of their agents carrying out authorized business was interfered with.
We are authorized to send private individuals to do this, and those individuals may do so without fear of being prosecuted by our country. The other country will obviously not recognize it as legal.
No country has ever recognized letters of marque and reprisal issued against it as legally valid. The value of the letters was that other countries would not treat holders as pirates or interefere with them.
Who cares? It’s end of story. Their stuff is gone, and there isn’t a thing they can do about it unless they want to come, fight, and lose even more stuff.
So you concede that if no one recognizes letters of marque and reprisal it is a pointless exercise to issue them.
Of course we are not obligated to respect letters of marque served upon our own interests. That would be ridiculous. Our military and law enforcement are permitted, if not obligated, to engage anyone who tries.
Which is the position that every country takes and has always taken.
I repeat: letters of marque and reprisal serve no purpose today, they are not a substitute for military deployment, and they are completely redundant in the presence of large monetary bounties as an inducement for private citizens to join the hunt.